JP2001133906A - Picture reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive flat bed type picture reader using a contact image sensor, which is manufactured at a low cost and is easily made small- sized. SOLUTION: An adapter 119a provided with rolls 114a and 114b made of slidable plastics as contact members and an adapter 199b provided with a roll 114c made of slidable plastics as a contact member are provided in both ends in the lengthwise direction of a contact image sensor 102. These adapters 199a and 199b are fixed to the contact image sensor 102 by screws or the like. Both side faces, namely, guide faces 115a and 115b of a platen glass parallel with the scanning direction of the contact image sensor 102 are held between these contact members to settle the attitude in the horizontal (lengthwise) direction of the contact image sensor 102.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a flat bed type image reading apparatus incorporating a contact type image sensor.

[0002]

2. Description of the Related Art FIGS. 17 and 18 show the structure of a conventional image reading apparatus having a built-in contact image sensor. In particular, FIG. 17 is a perspective view showing a schematic configuration of the image reading apparatus.
FIG. 18 is an enlarged plan view showing a contact image sensor incorporated as a part of the image reading apparatus.

[0003] As shown in FIG.
Numeral 0 denotes a light-transmitting plate 601 serving as a document mounting table, a pressure member 610 covering the light-transmitting plate when reading a document, and a light-transmitting plate 6.
01, a contact type image sensor 602 that moves on the back side of the original placing surface and scans image information of the original, a light source (eg, LED) (not shown), a guide shaft 609, and a drive motor 6
11. It is provided with a tow wire rope 613 and the like.

As shown in FIG. 18 in an enlarged manner, a light guide 603 and a light guide 603 are provided inside the contact type image sensor 602.
In addition to lens array 604, linear sensor 605, etc., LE
D (not shown) is incorporated, and these components constitute one optical system unit.

When reading an original, the LED housed in the sensor holder 607 emits light, and the light is converted into a linear shape by the light guide 603 to irradiate the original surface. The image of the original is formed on the surface of the linear sensor 605 by the lens array 604, and is photoelectrically converted by the linear sensor 605. At the same time, the drive motor 611
Is driven, and the driving force is transmitted to the close contact type image sensor 602 via the tow rope. Then, the contact image sensor 602 (the entire optical system unit) moves along the guide shaft 609 and scans the original. The guide shaft 609 has its axial direction fixed in advance along the scanning direction of the contact image sensor 602, and has a function of guiding the trajectory of the contact image sensor 602.

On the other hand, the contact type image sensor 602 is incorporated in a sensor holder 607. Biasing members (springs) 608a and 608b are disposed between the sensor holder 607 and the contact type image sensor 620. Energize.

[0007] Contact members (spacers) 606a and 606b are provided at contact portions between the contact image sensor 602 and the rear surface of the light-transmitting plate material 601.
The slidability between the two members 601 and 602 is also ensured while keeping the distance between the contact member 1 and the contact type image sensor 602 constant. In addition, a method is also known in which the exterior member of the contact image sensor is formed of slidable plastic, and the contact portion is integrated.

Incidentally, an image reading apparatus as described above, that is, a flat original is placed on a similarly flat mounting table, and the contact type image sensor is placed in a direction (scanning direction) orthogonal to the longitudinal direction of the image sensor. 2. Description of the Related Art An image reading apparatus that scans a document by reading an image while moving it in a straight line is widely known as a flatbed image reading apparatus.

In recent years, the demand for such a flat-bed type image reading apparatus has been further increased, and demands for downsizing and low price have been increasing.

[0010]

By the way, in such a flat bed type image reading apparatus, the guide shaft 609 (FIGS. 17 and 18) is required to secure an appropriate trajectory along the scanning direction of the contact type image sensor. Guide member) is an essential component.

For example, when a guide shaft is applied as a guide member, the guide shaft shown in FIG.
In general, at least one guide shaft is provided in a space below the contact image sensor (the side opposite to the placed document) as in the apparatus described in Japanese Patent Application Publication No. 270896.
For this reason, it is necessary to secure a guide space below the contact type image sensor, which has been a barrier to miniaturization of the apparatus in the height (thickness) direction.

Further, in order to dispose the guide shaft in the apparatus, a fitting hole for engaging the guide shaft with the sensor holder is provided, the guide shaft is penetrated through the fitting hole, and a towing wire is wired. In addition, the guide shaft may be processed with a lead screw or a lead shaft, but such a configuration is
This will further complicate the structure and increase the size of the device.

As means for reducing the size of the apparatus in the height direction (the direction perpendicular to the original placing surface), Japanese Patent Laid-Open No. 7-193689 is used.
As disclosed in Japanese Patent Application Laid-Open Publication No. H11-209, a method of arranging a guide shaft at a longitudinal end of the contact type image sensor and substantially on the same plane as the contact type image sensor is also conceivable.

However, in this case, another problem arises in that the size of the contact type image sensor in the longitudinal direction of the device increases, and the width of the device, that is, the installation area of the device increases.

On the other hand, a relatively expensive metal cutting rod (5 mm in diameter) is required for the guide shaft to satisfy linearity and slidability.
(About 10 mm). In the manufacture of such a bar, material costs are increased, and labor such as cutting is also required. This increases the manufacturing cost of the image reading apparatus.

The present invention has been made in view of such circumstances, and has as its object to be manufactured at a low cost as a flatbed type image reading apparatus using a contact type image sensor. It is an object of the present invention to provide an inexpensive and easily miniaturized image reading apparatus.

[0017]

In order to achieve the above object, the present invention provides a light-transmitting plate on which a document is placed, and a predetermined track on the back side of the document-mounting surface of the light-transmitting plate. Move up,
In an image reading apparatus provided with image information scanning means for scanning the image information of the document and guide means for guiding the trajectory of the image information scanning means, the translucent plate member is substantially scanned by the image information scanning means. The guide means is connected to the image information scanning means, and moves along the side edge of the light-transmissive plate to scan the image information. The gist is to guide the trajectory of the means.

Further, a contact portion provided on the guide means and in contact with a side edge portion of the translucent plate member and moving in contact along the side edge portion, and a corresponding contact portion is provided on the side edge portion. A biasing means for biasing the head toward the head.

The image information scanning means further comprises guide means corresponding to both side edges of the translucent plate formed along the scanning direction of the image information scanning means, and the contact portions provided on the both guide means. Is substantially perpendicular to the original placing surface of the translucent plate member, and abuts on both side surfaces formed along a substantially scanning direction of the image information scanning means to sandwich the translucent plate member. Is also good.

The contact portion may be formed of a rolling member that contacts the side edge portion and rolls on the side edge portion.

Further, the contact portion may be formed of a sliding member that contacts the side edge portion and slides on the side edge portion.

Further, a sliding coating may be provided on the sliding surface of the sliding member in the side edge portion.

[0023] The guide means may be a first abutment which is substantially perpendicular to the original placing surface of the translucent plate member and abuts on both side surfaces formed along a substantially scanning direction of the image information scanning means. A contact portion, first biasing means for biasing the first contact portion toward the contact surface, and a second biasing portion for contacting the original mounting surface of the translucent plate or the back surface thereof The apparatus may further include a contact portion and a second urging means for urging the second contact portion toward the contact surface.

Further, the length of the connecting portion between the image information scanning means and the guide means may be variable along the longitudinal direction of the image information scanning means.

Further, an elastic member may be provided at a connecting portion between the image information scanning means and the guiding means, and biases the guiding means toward the image information scanning means.

According to the above configuration, all the movement guide functions of the image information scanning means in the scanning direction can be concentrated near the side edges of the translucent plate member, and the image reading apparatus can be downsized. At the same time, it is possible to abolish the guide shaft which increases the cost, and the manufacturing cost is reduced.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which the present invention is applied to a flatbed scanner will be described below with reference to FIGS.

FIG. 1 is a perspective view showing a schematic configuration of a document reading section in a flatbed type scanner (hereinafter, referred to as a scanner) according to the first embodiment.

As shown in FIG. 1, the original reading section (100a) of the scanner 100 mainly includes an original platen glass 101, a contact image sensor 102, a drive motor 111, a tow wire rope 113, and the like. ing.

The platen glass 101 is a rectangular flat plate made of a transparent glass having a thickness of about 3 mm, and one surface thereof is used as a document placing surface. The long contact image sensor 102 is provided on the back side of the original placing surface of the original platen glass, and incorporates a well-known optical system unit (not shown) necessary for photoelectrically converting image information of the original. . Further, both side edge portions (side edge portions) 11 of the document table glass 101 formed in parallel with the scanning direction (of the contact type image sensor) shown in FIG.
Sides 115a and 115b, which form part of 5A and 115B, face the original platen glass of the contact type image sensor 102, which is polished to enhance the slidability and linearity with a contact member described later. A convex member (contact member) 106 made of a sliding plastic such as polyacetal is provided on the surface
a, 106b and 106c are provided.

FIG. 2 is a side view of the document reading section 100a shown in FIG. 1 as viewed in the direction of arrow II, and FIG.
FIG. 3 is a cross-sectional view showing a cross section taken along line III-III.

As shown in both figures, the lower surface (bottom surface) 102b of the contact type image sensor is provided with leaf springs 120a, 120b at both ends in the longitudinal direction.
The contact type image sensor 102 is urged toward the platen glass 101 by a reaction force with the platen 18. As a result, the posture of the contact type image sensor 102 in the vertical direction (axial direction perpendicular to the document placing surface) is determined, and the distance between the document table glass 101 and the contact type image sensor 102 is kept constant.

In this embodiment, the leaf springs 120a,
120b and the inner wall 1 of the outer case 118 in contact with the leaf spring
The surface 18a is formed of a conductive material, and functions as a ground for the contact type image sensor 102.

Further, in place of the leaf spring 120a used in the present embodiment, any biasing means other than an elastic member such as a coil spring can be applied.

Further, the convex member provided on the upper surface of the contact type image sensor may be used as a contact member such as a roller.

On the other hand, an adapter 19a provided with rollers 114a and 114b formed of slidable plastic as contact members at both ends in the longitudinal direction of the contact type image sensor 102, and also formed of slidable plastic. Adapter 19a provided with roller 114b as a contact member
Is provided. The adapters 19a and 19b are fixed to the contact image sensor 102 with screws or the like.
With these contact members, both side surfaces (guide surfaces) 115 of the platen glass parallel to the scanning direction of the contact image sensor 102.
By sandwiching a and 115b, the posture of the contact image sensor 102 in the left-right direction (longitudinal direction) is determined.

By the way, the guide surface 1 of the platen glass 101
The distance L between the guide plate 15a and the guide surface 115b is slightly different for each platen glass. In consideration of this, in the present embodiment,
One adapter 119b and contact type image sensor 102
Is connected via the hinge 117 and the connecting member 116, and the left and right contact members 114a (114b)
And 114c are adjustable (variable). By applying such a variable distance (length) configuration, it is possible to suitably prevent and suppress the occurrence of inconveniences such as play in the left-right direction (longitudinal direction of the contact-type image sensor 102) and poor running. become.

On the other hand, a tow wire rope 113 is fixed to the contact type image sensor 102. The wire rope 113 is wound around a wire take-up glue 112 connected to the drive motor 111. At the time of reading a document, the contact type image sensor 10 is
Reference numeral 2 denotes a back surface and both side surfaces 115a and 11 of the platen glass 101.
It moves linearly in the scanning direction using 5b as a guide surface. Thus, the image information of the document placed on the document placing surface is read by the optical system unit incorporated in the contact image sensor 102.

By the way, both side surfaces (guide surfaces) 115a and 115b of the document table glass 101 are in contact with the contact members (rollers) 11.
As described above, polishing is performed to enhance the slidability and linearity with 4a and the like. If this polished surface is finished to the surface of the platen glass, the contact member can be a sliding member instead of a roller. With such a configuration, the same effect as in the present embodiment can be obtained.

As shown in FIGS. 4 and 5, the apparatus may be configured to guide the trajectory of the close contact type image sensor 102 using the original placing surface of the original platen glass 101 as a guide surface. That is, the coil spring 1 as an urging means is provided between the contact type image sensor 102 and the platen glass 101.
20a and 120b are provided and biased to the back of the platen glass (see FIG. 5). On the other hand, the contact type image sensor 1
L is formed on the adapter 119a and the adapter 119b by projecting L-shaped claws 106a ', 106b', and 106c ', and the main body of the contact type image sensor 102 is moved from the document placing surface of the platen glass 101 by the claws. To support. Note that, instead of the coil springs 120a and 120b, another urging member or an elastic member such as a leaf spring may be used.

According to the scanner of this embodiment configured as described above, the function of guiding the movement of the contact type image sensor 102 in the scanning direction is entirely performed by the side surface 1 of the platen glass 101.
It becomes possible to consolidate the scanners in the vicinity of 19a and 119b, that is, in the vicinity of the side edge, and it is easy to reduce the size of the scanner. Also, by applying the above configuration, the guide shaft which has been used as a conventional guide means for guiding the trajectory of the contact type image sensor, but has been problematic in terms of high cost and poor mountability can be eliminated. And the manufacturing cost is reduced,
The mountability of the contact type image sensor on the scanner is also improved.

The adapter 119a and the adapter 11
9b securely holds the platen glass 102 from both sides via the contact portion, so that the engagement state between the contact portion and the side edge portion is sufficient over the entire length of the side edge portion for the track guide. It will be held suitably. Therefore, the reliability of the function related to the image reading can be sufficiently secured while maintaining the mountability of the members and the like necessary for the trajectory guidance of the image information scanning means.

(Second Embodiment) Next, a second embodiment in which the present invention is applied to a flatbed type scanner will be described with reference to FIGS.

Here, even in the second embodiment,
A scanner as an image reading device is generally described as the first type.
A document table glass, a close contact image sensor, a drive motor, a tow wire rope, and the like, which are substantially the same as those of the first embodiment. Therefore, the same reference numerals as in the first embodiment denote the same basic components of the scanner, and a detailed description thereof will be omitted.

FIG. 6 is a perspective view showing a schematic configuration of a scanner 200 (reading section 200a) according to the second embodiment of the present invention. FIG. 7 is a view of the reading section 200a viewed in the direction of arrow VII. It is a side view.

As shown in both figures, in this embodiment, one of the adapters 119a and 119b provided at both ends in the longitudinal direction of the contact type image sensor 102 is used.
9b is urged toward the side surface (guide surface) 115b of the platen glass by a spring 221 as an urging member, and the longitudinal direction of the contact type image sensor 102 (the platen glass 102
It is attached to the contact type image sensor so as to be movable in an axial direction perpendicular to the scanning direction (above). As a result, even when the distance L between both sides of the platen glass partially varies, the spring expands and contracts, so that rattling and running failure can be suitably prevented and suppressed.

As shown in FIGS. 8 and 9,
As a modification of the present embodiment, the two towing wire ropes 113a and 113b are connected to both side edges 1 of the platen glass 101.
15A, 115B, each wire rope 11
3a, 113b and the contact type image sensor 102 are coupled near both ends in the longitudinal direction of the sensor,
Contact image sensor 10 with two wire ropes
The device may be configured to have a so-called double-sided drive configuration, such as moving the second drive.

As shown in FIGS. 10 and 11, as another modified example of this embodiment, the contact type image sensor 102 and both the adapters 119a and 119b provided at the longitudinal ends thereof are used. May be provided with urging members (springs) 221a and 221b, respectively.

That is, the contact type image sensor 102 is urged from both sides of the platen glass 102 and connected to the contact type image sensor 102 in the longitudinal direction (axial direction orthogonal to the scanning direction on the platen glass 102). The configuration may be such that the part is movable. With such a configuration, the contact-type image sensor 102 maintains a stationary state by balancing the urging forces of the right and left urging means (springs). As a result, even if unevenness occurs on one of the guide surfaces, the amount of displacement of the contact type image sensor in the longitudinal direction can be effectively reduced by a spring located closer to the image sensor.

For example, FIG. 12 is a plan view of a part of the reading unit 200b (near the close contact type image sensor 102) of the scanner 200 according to the second embodiment as viewed from the original placing surface of the original platen glass 101. FIG. 13 shows how the connection portion of the adapter and the contact type image sensor is formed in the apparatus when there is a 1-mm recess (recess) on one side surface (guide surface) 115a in the longitudinal direction of the sensor 102 on the platen glass 101. FIG. 9 is an enlarged plan view showing the connection portion to be displaced in FIG.

As shown in FIG. 13, when the contact portion 114a moves 1 mm to the right in the drawing according to the shape of the recess of the guide surface 115a, the spring 221a as the urging member is contracted by 1 mm. In this state, the left and right springs (22
1a and 221b; refer to FIG.
21a and 221b) are different from each other, and the balance cannot be obtained. Therefore, the springs 221a, 221
In order to maintain the balance, for example, if both springs have the same spring constant, b will shrink (displace) with the same amount of shrinkage (each about 0.5 mm).

That is, the amount of movement of the contact type image sensor is also 0.5 mm, and the amount of movement of the contact type image sensor due to the concave portion of the guide surface is provided only by a biasing member (spring) at the connection portion between one end of the sensor and the adapter. Is reduced by half compared with the case where

Therefore, the displacement of the contact type image sensor 102 in the longitudinal direction, which appears as the deterioration of the image, can be suitably suppressed.

Furthermore, since the accuracy of the flatness (linearity) of the guide surface of the platen glass may be slightly reduced, the manufacturing cost of the platen glass can be reduced.

Further, the glass is liable to generate minute chips called pills on the peripheral side surface due to vibration or impact. According to the present invention, the influence of irregularities on the guide surface due to these pills is less likely to occur, and image deterioration is prevented or suppressed.

Further, by bringing the contact portions into a movable state via biasing means, when a vibration or impact is applied to the apparatus, other effects such as a reduction in the force applied to the guide surface or the close contact type image sensor are reduced. Will also be played.

That is, according to the scanner of this embodiment,
In addition to the effects provided by the first embodiment, even if the side edge (side surface) of the original platen glass has some distortion, unevenness, or the like, an elastic member serving as an urging means, that is, a spring 221, By the action of the springs 221a and 221b, the engagement state between the close contact type image sensor 102 and the platen glass 101 is more preferably achieved over the entire length of the side edges (side surfaces 115a and 115b) on which the sensor 102 guides the track. Will be retained. Therefore, the reliability of the function related to image reading is sufficiently ensured.

The springs 221a, 221b, 221c
Instead, another urging member or elastic member such as rubber or elastic resin may be applied. (Third Embodiment) Next, a third embodiment in which the present invention is applied to a flatbed type scanner will be described with reference to FIGS.

Here, even in the third embodiment,
A scanner as an image reading device is generally described as the first type.
And a document table glass, a contact image sensor, a drive motor, a pulling wire rope, an adapter, and the like substantially the same as those of the second embodiment. For this reason, basic components of the scanner are denoted by the same reference numerals as those in the first and second embodiments, and detailed descriptions thereof are omitted.

FIG. 14 is a perspective view showing a schematic configuration of a scanner 300 (reading unit 300a) according to the third embodiment of the present invention. FIG. 15 shows the reading unit 300a with an arrow XIII.
It is the side view which looked at in the direction. FIG. 16 is an enlarged plan view showing one end in the longitudinal direction of the contact type image sensor forming a part of the reading unit 300a.

As shown in FIGS. 14 and 15, the reading section 300a of the scanner 300 according to the present embodiment comprises, similarly to the modification of the second embodiment, both ends in the longitudinal direction of the contact type image sensor, and an adapter. Are provided with urging members (springs) at the connecting portions of the respective members.

The scanner 300 according to the present embodiment also has a slidable property such as high-molecular polyethylene or Teflon having a thickness of about t = 0.2 mm on both sides (guide surfaces) of the contact type sensor 102 in the document table glass 101 in the longitudinal direction. Tape 32
2a and 322b are affixed, making this configuration a further feature (see also FIG. 16).

That is, such a slidable tape 32
By attaching 2a and 322b to the guide surface of the contact type image sensor 102, minute irregularities on the side surface of the platen glass are covered. For this reason, when manufacturing the platen glass 101 as a component of the scanner, the guide surface 115 is used.
Even if the degree of polishing on both side surfaces a and 115b becomes somewhat rough, there is no problem. As a result, the manufacturing process is simplified, which contributes to cost reduction.

In FIG. 15, the slidable tape is stuck on both sides. For example, one side of the platen glass is polished smoothly by polishing, and the other side is roughened to a rough side. A configuration may be adopted in which a slidable tape is applied only to the side surface of.

Further, as shown in FIG. 16, if a slidable tape is attached to both sides of the guide surface of the original table glass 101 and the rear surface (front surface), the upper and lower sides of the contact type image sensor can be moved. Direction (for example, the axial direction perpendicular to the document placing surface)
Slidability is also improved. In addition, it is possible to contribute to a reduction in driving force for moving the contact image sensor in the scanning direction.

As described above, according to the scanner of the present embodiment, the following effects are expected in addition to the effects obtained by the above embodiments.

That is, even if the surfaces of the side surfaces 115a and 115b are slightly rough, a smooth scanning operation by the close contact type image sensor 102 is sufficiently ensured.

Furthermore, this tape is also effective in preventing the glass from being scattered in the event that a pilling on the guide surface or a crack or the like should occur on the original table glass.

[0069]

As described above, according to the present invention,
By using the front and rear surfaces of the platen glass and both side surfaces parallel to the scanning direction of the contact image sensor as guides for moving the contact image sensor, it is possible to reduce the size and cost of the apparatus.

Also, at least one of the contact portions in the left-right direction of the contact type image sensor is urged by the urging member to the guide surface on the side surface of the platen glass, and the distance between the left and right contact members is moved. In addition, variations in the distance between the guide surfaces in the left-right direction of the platen glass are absorbed.

Further, the right and left contact members are urged by the urging members to the guide surfaces on both sides of the platen glass, so that the amount of shake of the contact type image sensor due to the unevenness of the guide surfaces can be reduced. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a scanner according to a first embodiment of the invention.

FIG. 2 is a side view showing a reading unit of the scanner.

FIG. 3 is a cross-sectional view of FIG. 2 taken along the line III-III.

FIG. 4 is a perspective view showing a modified example of the scanner according to the first embodiment.

FIG. 5 is a side view showing a reading unit of the scanner.

FIG. 6 is a perspective view illustrating a schematic configuration of a scanner according to a second embodiment.

FIG. 7 is a side view showing a reading unit of the scanner.

FIG. 8 is a perspective view showing a modified example of the scanner according to the second embodiment.

FIG. 9 is a side view showing a reading unit of the scanner.

FIG. 10 is an exemplary perspective view showing another modification of the scanner according to the second embodiment;

FIG. 11 is a side view showing a reading unit of the scanner.

FIG. 12 is a plan view showing a part of a reading unit of the scanner according to the second embodiment.

FIG. 13 is an enlarged plan view showing a connection portion between the adapter and the contact type image sensor.

FIG. 14 is a perspective view illustrating a schematic configuration of a scanner according to a third embodiment.

FIG. 15 is a side view showing a reading unit of the scanner.

FIG. 16 is an enlarged plan view showing one end in the longitudinal direction of the contact image sensor.

FIG. 17 is a perspective view showing a schematic configuration of a conventional image reading apparatus.

FIG. 18 is an enlarged plan view showing a contact image sensor attached as a part of a conventional image reading apparatus.

[Explanation of symbols]

101 Platen glass (translucent plate material) 102 Contact image sensor (image information scanning means) 106a, 106b, 106c Spacer (distance holding member) 111 Drive motor 112 Wire take-up tall 113 Tow wire rope 114a, 114b , 114c Roller (contact member) 115a, 115b Guide surface 116 Connecting member 117 Hinge 118 Outer case 119a, 119b Adapter 100a Scanner reading unit

Claims (9)

[Claims] 1. A translucent plate on which an original is placed, and an image information scanner which moves on a predetermined track on the back side of the original placing surface of the translucent plate to scan image information of the original. Means, and a guide means for guiding the trajectory of the image information scanning means, wherein the translucent plate member has a side edge formed substantially along the scanning direction of the image information scanning means. The image reading device is characterized in that the guide unit is connected to the image information scanning unit, and guides the trajectory of the image information scanning unit by moving along a side edge of the translucent plate member. apparatus. 2. The image reading apparatus according to claim 1, further comprising: a contact portion provided on said guide means, said contact portion being in contact with a side edge of said translucent plate member, and moving along said side edge. And an urging means for urging the contact portion toward the side edge. 3. The image reading apparatus according to claim 2, further comprising: a guide unit corresponding to each of both side edges of the translucent plate formed along a scanning direction of the image information scanning unit. The abutting portion provided on the guide means abuts on both side surfaces formed substantially orthogonal to the original placing surface of the translucent plate material and substantially along the scanning direction of the image information scanning means. An image reading device comprising a transparent plate material sandwiched therebetween. 4. An image reading apparatus according to claim 3, wherein said contact portion comprises a rolling member which contacts said side edge portion and rolls on said side edge portion. 5. An image reading apparatus according to claim 3, wherein said contact portion comprises a sliding member which comes into contact with said side edge portion and slides on said side edge portion. 6. The image reading apparatus according to claim 5, wherein a slidable coating is provided on a sliding surface of the sliding member in the side edge portion. 7. An image reading apparatus according to claim 1, wherein said guide means is substantially perpendicular to a document placing surface of said translucent plate material and is substantially equivalent to said image information scanning means. A first abutting portion that abuts on both side surfaces formed along the scanning direction; a first biasing unit that biases the first abutting portion toward the abutting surface; A second contact portion that contacts the original placing surface of the optical plate material or the back surface thereof, and a second urging unit that urges the second contact portion toward the contact surface. An image reading apparatus, comprising: 8. The image reading apparatus according to claim 1, wherein a length of a connecting portion between the image information scanning means and the guide means is variable along a longitudinal direction of the image information scanning means. Image reading device. 9. An image reading apparatus according to claim 1, wherein said image reading means is provided at a connection portion between said image information scanning means and said guide means, and said guide means is attached to said image information scanning means. An image reading apparatus comprising an elastic member for urging.